The present invention concerns a drilling device intended to equip lathes in order to permit drilling of radial holes in a part.
In the metal shaping field, a great number of parts which are machined with the aid of lathes require the drilling of a transverse hole along one of its diameters.
The drilling is performed with a drill bit arranged radially on the lathe and designed to pierce the abutting part along its diameter. Drilling the holes, however, presents many drawbacks, especially the drawback of requiring the part to be drilled remaining stationary in order to permit the drilling. In addition, it requires the utilization of a tool which approaches radially on the side of the part. However, the space located laterally around the part, with the majority of the machine tools and notably lathes, is generally obstructed by equipment, for example oil inlets or sensors.
Consequently, the radial piercing tools currently utilized on lathes are not completely satisfactory, inasmuch as they somewhat lengthen the machining operations and, thus, slow down production and output of the machine tools at the production facility.
It is the object of the present invention to resolve the above mentioned drawbacks with the aid of simple, reliable and readily implementable means. Its aim is to facilitate the radial drilling operations which are performed on lathes and to accelerate said drillings by augmenting the lathe output.
According to its principal characteristic, the radial drilling device for a lathe according to the invention is for drilling a hole or holes radially in a rotating part supported by the lathe. It comprises drilling means formed by at least one drill bit, held by a mobile drilling jaw in a transverse plane, orthogonal to the rotational axis of the part to be drilled. It is characterized in that it comprises a principal rotational drilling set which carries the drilling means and causes the drilling means to rotate around a longitudinal axis of rotation of the part at the same rotational speed as the speed of the part to be drilled, initiated by the lathe.
According to another characteristic of the radial drilling device for a lathe according to the invention, it is characterized in that the principal rotational drilling set is mounted on a counter-spindle of the lathe and is formed by two integral sub-assemblies rotating around the longitudinal axis of the device in order to undergo synchronized rotation with that of the part to be drilled. An auxiliary sub-assembly and a drilling sub-assembly whose movement relative to the auxiliary sub-assembly controls the radial movement of the drilling jaw or drilling jaws.
According to a complementary characteristic of the radial drilling device for a lathe according to the invention, it is characterized in that it is installed on the lathe in the extension of the part to be drilled, in order to be longitudinally displaced according to the rotational axis of the part, said displacement initiating the relative movement of the auxiliary and drilling sub-assemblies.
According to the preferred specific embodiment of the radial drilling device for a lathe according to the invention, the principal rotational set comprises a drilling sub-assembly which radially supports the drill bits by the obliquity of the mobile drilling jaws and an auxiliary sub-assembly whose relative movement in translation according to the longitudinal axis of the device relative to the drilling sub-assembly causes the radial displacement of drilling jaws by virtue of a system of complementary slopes and support surfaces.
According to this embodiment, the drilling sub-assembly comprises a principal control element that is put into motion by the part to be drilled in relation to the support sub-assembly, at the time of the longitudinal displacement between the device and the part in order to carry along in longitudinal translation the drilling jaw or drilling jaws which present the complementary slopes that cooperate with the support surfaces of a support element of the support sub-assembly.
In addition, the radial drilling device for a lathe comprises a driving assembly that causes the drill bit or drill bits to rotate around their own axis.
According to a complementary characteristic of the radial drilling device for a lathe according to the invention, it is characterized in that the drill bit or drill bits is/are mounted freely rotating in the drilling jaw or jaws and carry pinions that engage a drive ring of the immobile drive set in rotation when the jaws carried by the rotational set cause a rotation around the longitudinal axis of the device.
According to the preferred specific embodiment of the radial drilling device for a lathe according to the invention, the pinions of the drill bits and the driving ring cooperate by enmeshment regardless of the radial position of the drilling jaws that carry the drill bits.
According to another characteristic of the radial drilling device for a lathe according to the invention, it is characterized in that the driving ring is mounted on a stationary, rotatable element in rotation around the longitudinal axis, but integral in longitudinal displacement of the drilling sub-assembly in order to keep the pinions and the driving ring in cooperation.
According to the preferred specific embodiment of the radial drilling device for a lathe according to the invention, it is characterized in that it comprises two diametrically opposed drill bits, carried by two drilling jaws.